WASHINGTON -- On Dec. 6, 2007, while she was away from the Senate pursuing the presidency, Sen. Hillary Clinton asked Majority Leader Harry Reid to introduce her bill S. 2426 to prohibit funding for implementing any agreement with Iraq "involving 'commitments or risks affecting the nation as a whole,' including a status of forces agreement," unless Congress has approved such an agreement. The "commitments or risks" language is from State Department criteria for when congressional approval should be sought for international agreements.

Clinton declared it "outrageous that the Bush administration would seek to circumvent the U.S. Congress on a matter of such vital interest to national security." Clinton's co-sponsors included Barack Obama and John Kerry, who now chairs the Foreign Relations Committee.

Last Aug. 1, Sen. Joe Biden introduced S. 3433 to prohibit funding for a "security commitment to, or security arrangement with" Iraq that has not been approved by Congress. Biden was indignant that "Iraq's leaders plan to submit the agreement to their parliament -- but our president does not." Iraq's parliament has debated and ratified the agreement called "On the Withdrawal of United States Forces from Iraq and the Organization of Their Activities during Their Temporary Presence in Iraq."

It stipulates U.S. duties "while conducting military operations" as part of "temporary assistance" to the Iraqi government when acting against "al-Qaeda and other terrorist groups, outlaw groups, and remnants of the former regime." And: "In the event of any external or internal threat or aggression against Iraq that would violate its sovereignty, political independence, or territorial integrity, waters, airspace, its democratic system or its elected institutions, and upon request by the government of Iraq, the parties shall immediately initiate strategic deliberations and, as may be mutually agreed, the United States shall take appropriate measures, including diplomatic, economic, or military measures, or any other measure, to deter such a threat." Sen. James Webb, a Virginia Democrat who co-sponsored both the Clinton and Biden bills, said "any" agreement with Iraq should earn "the explicit consent of Congress."

Granted, the United States has "status of forces agreements" with about 115 countries and most of these SOFAs were created solely by executive actions. The new agreement with Iraq is, however, more consequential than a normal SOFA. Besides, after all the American blood and treasure sunk in Iraq, and after the deep divisions among Americans caused by the way the war was justified and the occupation was conducted, any negotiated arrangement that formalizes ongoing U.S. security commitments or assurances to Iraq should take the form either of a treaty requiring a two-thirds vote of the Senate or a "congressional-executive agreement" requiring simple majorities in both houses of Congress.

As senators, the current president, vice president and secretary of state took their stands on the principle that the legislative and executive branches share foreign policy responsibilities. It is, however, axiomatic that where you stand depends on where you sit, and Obama, Biden and Clinton now sit in the executive branch. So perhaps they will be less inclined to stand on the principle that power should be divided so that important decisions will be debated by rival sources of responsibility. Situational constitutionalism is not new, but if Obama, Biden and Clinton now embrace it they will continue -- and ratify -- the executive branch aggrandizement by the previous administration.

As Democrats, Clinton, Obama and Biden were concerned before the election that President George W. Bush might bind his successor to repugnant policies. There is, however, a larger matter still at issue -- the constitutional balance of executive and legislative responsibilities regarding foreign relations. Even were it certain -- it is not -- that U.S. forces will be out of Iraq on a particular date, that would not drain the constitutional question of its salience.

America, having nurtured constitutional government in Baghdad, should not neglect it here. If Congress is going to rebuild some of the institutional muscle that has atrophied from disuse under majorities of both parties and in relation to presidents of both parties -- if Congress is going to regain responsibilities it forfeited to the executive branch during the Cold War and other undeclared wars -- Congress must debate the new agreement with Iraq. Besides, it would be instructive, and entertaining, to watch many Democrats reluctantly join many contented Republicans in praising an agreement, perhaps modified by this president, to continue a U.S. presence in Iraq of perhaps 50,000 troops, a presence that surely involves "commitments or risks affecting the nation as a whole."